Exercise machines include both resistance machines (e.g., weight machines, spring-loaded machines, etc.) and endless-path machines (e.g., exercise bikes, treadmills, elliptical trainers, etc.), and are typically used to enhance the strength and/or conditioning of the user. Various endless-path machines, such as exercise bikes, have recumbent or seated configurations that are intended to decrease the overall impact load on the body and/or to work different muscles than upright exercise machines. Recumbent exercise machines can also accommodate persons with limited mobility, decreased ranges of motion, and/or other health concerns, and may be used for rehabilitation and/or physical therapy in a clinical setting or at home. Recumbent bikes and stepper devices, for example, can provide a means for lower body exercise and/or physical therapy for users with injured legs or arms and/or cardiovascular concerns.
U.S. Pat. No. 5,356,356 to Hilderbrant et al., for example, is directed to a recumbent exercise device that includes a pair of pedals attached to a corresponding pair of leg levers and a pair of arm levers. The leg and arm levers are pivotally supported by a frame for movement about a transverse pivot axis, and are connected to each other for contralateral movement that simulates a walking motion. A magnetic resistance mechanism is coupled to the arm and leg levers to provide resistance about the pivot axis of the levers. U.S. Pat. No. 6,790,162 to Ellis et al. is directed to a recumbent stepper device similar to that of U.S. Pat. No. 5,356,356, except the arm and leg levers are not pivotally disposed on the same axis. This independent coupling increases the range of motion of the arm and leg levers. These recumbent stepper devices, however, provide only a single stepping motion without the ability to change the leg path, range of motion, and/or other parameters of the exercise device.